Motorized weighing conveyor

ABSTRACT

There is disclosed a commodity transport conveyor mounted on a weighing device; the conveyor being powered by a drive roller housing an electric motor. The stator of the motor is fixed to the conveyor frame and the rotor of the motor drives the roller and is in dynamic balance therewith.

BACKGROUND OF THE INVENTION

This invention relates to commodity transport/weighing machines such asare used in the food packaging/processing and similar industries; andmore specifically to transport means for moving goods packaged in casesor bags or the like across weighing platforms such as at so-called "onthe fly" speeds. Load cells or other weight-responsive transducers aretypically connected to the weighing platform for determining andindicating and/or recording the weights of the transported items.Arrangements for such purposes are shown for example in my earlier U.S.Pat. Nos. 3,180,475 and 4,114,707. However, in such systems, it isimperative that the weighing platform be protected againstvibratory/resonance impact forces incidental to the weighing operationsuch as would interfere with the accuracies of the container weightmeasurements.

OBJECTS AND BRIEF SUMMARY OF THE INVENTION

The present invention provides an improvement in the packagetransport/weighing industry; whereby intolerable previously encounteredoperational vagaries of such prior control systems are avoided. Thisinvention provides an improved system whereby that part of the systemwhich conveys the items to be weighed in succession across the weighingplatform is isolated from heretofore disturbing externally generatedinfluences, such as are inevitably induced in prior art systems by wayof the gear/chain/belt drive mechanism or the like which operativelyconnects the remotely located power supply motor to the roller drivingthe over-the-platform conveyor.

The present invention is characterized in that the over-the-scaleconveyor system is powered by an electric motor, the rotor of which iskeyed to and arranged in dynamically balanced relation with thestructure of the driving roller of the conveyor. Thus, vibratory inputsare avoided such as are typically imposed on conveyor systems employingremotely stationed solidly-based drive motors having interconnectingpower transmission devices such as chain and sprocket; V-belt and sheavedrive systems; and the like which require tensioning devices and safetyguard devices. The requisite use of such arrangements inevitably producein such prior art systems inaccurate weighing "scale-fluttering"effects.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front elevational view of a package weighing/transportmechanism embodying the present invention;

FIG. 2 is a side elevational view taken as along line 2--2 of themechanism of FIG. 1; and

FIG. 3 is a fragmentary enlarged scale view taken partly in section asalong line 3--3 of FIG. 1.

DETAILED SPECIFICATION

The drawing herewith illustrates a typical embodiment of the inventionin connection with a delivery conveyor as is generally designated at 10,and a take-off conveyor such as is generally indicated at 12. Thus, thesystem transports packages such as is shown at 14 across a weighing unitas is designated generally at 15, from the delivery conveyor 10 to thetake-away conveyor 12. It is of course to be understood that thedelivery and take-off conveyors may be of any suitably preferred types,and comprise per se no part of the present invention.

The combination weighing/transporting unit of the present invention asshown at 15 is mounted upon a frame structure 16, such as may be of theopen top channel-shaped configuration having oppositely upstanding sidewalls 18,19 as best shown at FIGS. 2 and 3. These side walls support infreely rotational manner at the opposite ends thereof conveyor supportrollers such as are shown at 20,22. Thus, the rollers 20,22 carry theendless conveyor belt 24 therebetween; and the unit structure comprisingframe 16; rollers 20,22; and conveyor belt 24 is mounted on aweight-sensing device such as is indicated generally at 25. Thisweighing device may be of any suitable type, and again per se comprisesno part of the present invention; and as shown may be carried upon asupport base 26 as is typical in the industry. The weightreading/recording facility in association with the weighing device 25 isshown at 27.

As shown in detail at FIG. 3 of the drawing in accord with one preferredform of the invention, the shell 22 of the conveyor driving roller ofthe unit is closed at one of its ends by an "end bell" 30 which isrigidly affixed thereto. The hub 46 of the end bell 30 is also keyed asshown at 31 to the rotor shaft 32 extending from the rotor 33 of anelectric motor such as is designated generally at 34. A support post 35which extends through the frame side wall 18 and is rigidly affixedthereto carries at its inner end the stator 36 of the motor 34 instationary position thereon. At its other end, the roller shell 22 isrotatably carried by means of an end bell 40 and bearings 42 upon a stubshaft 44 extending rigidly from the frame side wall 19. Thus, both endsof the drive roller 22 are rotationally supported on the frame and themotor 34 is located concentrically internally thereof; the motor drivingrotor 33 being thus disposed in harmoniously balanced relationship withthe conveyor drive roller assembly.

By virtue of this arrangement, the weighing operations conducted inconjunction with the conveyor are not encountered from externaldisturbances such as are typically imposed on a conveyor drive system ofthe type wherein a stationarily based power supply motor is locatedexternally thereof and its power is transmitted by means of aninterconnecting gear/belt/chain device or the like. Examples of suchprior art arrangements are shown in U.S. Pat. No. 4,023,668, and in myearlier patents 3,180,475 and 4,114,707. Note that the electrical powersupply line 50 to the motor of the unit of the present invention leadsfrom any suitable remotely located base support and enters the assemblythrough the post 35. The plasticity of the conductor 50 operateseffectively to absorb the almost imperceptible vertical floatingmovements of the unit 15 incidental to passage of successively weigheditems over the unit.

I claim:
 1. In a commodity weighing conveyor system which includes asupport base, a weight-sensing device on said support base, a framecarried by said weight-sensing device and an endless conveyor beltmounted on said frame, the improvement comprising means forsubstantially eliminating weighing errors incidental to operation ofsaid conveyor belt wherein:said frame includes upstanding side walls, afirst roller journalled between said side walls and a drive roller inspaced parallelism to said first roller, said conveyor belt beingtrained over said rollers, said drive roller including a cylindricalshell closed at one end by an end bell having a transverse wall spacedfrom said one end of the shell to define and end pocket therewith, saidtransverse wall having a centrally disposed hub provided with a boreopening into said pocket and having at least one keyway, an electricmotor disposed within said pocket and including a stator and a rotor,said stator having a hollow support post extending axially of said shelland through one of said upstanding side walls and secured theretowhereby to fix said stator to said frame, said rotor having an axiallyextending drive shaft fixed thereto and projecting into said bore inkeyed relation thereto whereby to rotatably drive said end bell directlyand in unison with said rotor, and electrical connector means projectingthrough said hollow support post for energizing said motor.
 2. In thesystem as defined in claim 1 wherein said conveyor belt is traineddirectly over said rollers so that generally parallel upper and lowerconveyor belt flights are defined, and including means for adjustingsaid first roller relative to said drive roller so as to tension saidbelt.